Lambert Conformal Format

The NARR model data is output onto a 349x277 Lambert Conformal Conic grid.
This has a resolution that is approximately 32km. The coverage area is shown in the two
maps below (both maps show the same data plotted).

In the netCDF file, the variables "lon" and "lat" contain those values for each of the coordinate pairs.
Reading the data is simply a matter of reading the 349x277 array. Plotting may be harder as the grid is irregular.
Below there are examples of how to plot the data in three commonly used packages.
GrADS and NCL are free. You must buy a license for IDL.

The XDEF and YDEF determine the interpolation. To change, from the 1x1 degree output, to a 1/3x1/3 degrees

XDEF 615 linear 150 .333
YDEF 255 linear 2 .333

Note that the 1st number is the number of x,y points (here it is 3 times the
1 degree values). The 150 and 2 are the starting longitudes and latitudes
respectively and the last number is the resolution.

In order to read NARR data into MATLAB we suggest that you use the mexnc and SNCTOOLS package at
http://mexcdf.sourceforge.net/. Because the packed NARR
data is roughly 500 MB per file, loading
and unpacking the data can cause MATLAB to run out of memory.
You can load only part of the file at a time by using:

nc_varget(filename,variablename,start,count)

For example,

p = nc_varget('prate.1979.nc','prate',[0 0 0],[10 -1 -1])

If the OpenDAP option is enabled for SNCTOOLS then a URL can be used in place of the filename.
Alternatively, you can solve the memory problem by using NCO ( http://nco.sourceforge.net/ )
to extract a subset of the data before loading it into MATLAB.
Here is a sample plot generated by interpolating the NARR data to a regular lat-lon grid: